Abstract: A dielectric loaded antenna, and method of designing same, for use in a high temperature environment, the antenna comprising an outer casing (14) of a material having a melting point of at least 1000° C., said outer casing (14) defining an inner channel, a first end of the channel defined by the casing defining a radiating aperture loaded with a section (Z4) of dielectric material of a first type which is chemically stable at a temperature of at least 1500° C., and a remaining length of said channel being loaded with sections (ZO-Z3) of at least one second type of dielectric material which is chemically stable at a temperature of at least 800° C., the dielectric constant of said first type of dielectric material being greater than that of the second type of dielectric material.

Abstract: A projectile detection system, and method of detecting a projectile (for example a bullet), for use on a vehicle (100) (for example a helicopter), the projectile detection system comprising: a radar antenna array (4) arranged to transmit and receive microwave signals so as to provide a plurality of detection segments (40, 42, 44, 46) of a volume of airspace (38); one or more processors (3) arranged to: determine which segments (40, 42, 44, 46) microwave signals reflected by a projectile (10) are received from; determine timing information relating to a time order in which the received microwave signals are received; and determine directional information relating to a direction of travel of the projectile (10) using the determined segments (40, 42, 44, 46) and the determined timing information; wherein the microwave signals have a frequency between 1 GHz and 30 GHz.

Abstract: A projectile detection system, and method of detecting a projectile (for example a bullet), for use on a vehicle (100) (for example a helicopter), the projectile detection system comprising: a radar antenna array (4) arranged to transmit and receive microwave signals so as to provide a plurality of detection segments (40, 42, 44, 46) of a volume of airspace (38); one or more processors (3) arranged to: determine which segments (40, 42, 44, 46) microwave signals reflected by a projectile (10) are received from; determine timing information relating to a time order in which the received microwave signals are received; and determine directional information relating to a direction of travel of the projectile (10) using the determined segments (40, 42, 44, 46) and the determined timing information; wherein the microwave signals have a frequency between 1 GHz and 30 GHz.